She said it was “heartbreaking” that many of the families who were at greatest risk of obesity were among the poorest in the country.

“A third of our children leave primary school overweight or obese,” she said.

“When I was at school you could tell the demography of children by how thin they were. You could see by looking at their eyes.”

They would be described as “the “skinny runts” because they were not getting the right food.

“When I go to my constituency, in fact when I walk around, you can almost now tell somebody’s background by their weight,” she said. “Obviously, not everybody who is overweight comes from deprived backgrounds but that’s where the propensity lies.”

Miss Soubry added: “It is a heartbreaking fact that people who are some of the most deprived in our society are living on an inadequate diet. But this time it’s an abundance of bad food.”

Often junk food tends to be “cheap” and parents think it is the only way to feed their children, she said. Even on her way to work at Westminster, she sees parents taking their children to fast food shops to buy them unhealthy “breakfast buns”, she said.

“They are not rich people, taking their children to school and they buy them breakfast.”

The “whole concept” of getting up in the morning at a regular time and eating a proper breakfast before leaving for work or school has disappeared in many homes, she said.

“Where I am in Nottingham, there is a Sainsbury’s and you see children going in there buying take away food, a sandwich, but more likely a packet of crisps, a fizzy drink, and that’s their breakfast.”

According to Department of Health figures, the poorest children are almost twice as likely to be obese than the richest.

Government figures published last month showed that 24.3 per cent of the most deprived 11 year-olds in England were obese, compared with just 13.7 per cent of children from the wealthiest homes.

Miss Soubry insisted she was not a "food fascist" and liked to eat sweets and pies "in moderation".

She said that, on average, individuals could reverse the rising obesity problem by eating 100 fewer calories every day.

Parents had “primary responsibility” to make sure their children are properly fed, but many struggled because families lived less structured lives.

“What they don’t do is actually sit down and share a meal around the table,” Miss Soubry told the Telegraph. “There are houses where they don’t any longer have dining tables. They will sit in front of the telly and eat.

“It doesn’t mean to say you can’t ever sit in front of the telly and have a meal,” she said. “But I believe children need structure in their lives, they need routine.”

Speaking at a conference hosted by the Food and Drink Federation, she warned food manufacturers they should cut the amount of fat, sugar and salt in their products voluntarily or ministers may have to force them to act through legislation.